Internal-combustion locomotive



Aug. 24 1926.

E. MRONGOVUS ET AL INTERNAL COMBUSTION LOCOMOTIVE Filed Jan* 13, 1925 3 Sheets-Sheet 1 WIM may

3 Sheets-Sheet 2 Filed Jan. 13,

E. MRONGOVIUS ET AL INTERNAL COMBUSTION LOCOMOTIVE Aug. 24 1926.

Aug. 24, 192s. 1,596,939

E. MRONGOVIUS ET AL INTERNAL COMBUSTION LOCOMOTIVE Filed Jan. 13. 1925 3 Sheets-Sheet I3 E. [WIW/290111: nos E. @c wuef Patented Aug. 24, 192.6.

UNITED `STATES PATENT OFFICE.

ERICH MRONGOVIUS, OF BERLIN, AND ERICH SCHWETER, OF BORNSTEDT, GERMANY, ASSIGNORS T0 THE FIR-M MAGNET-WERK G. M. B. H., EISENACH SPEZIALFABRIK FR ELEKTROMAGNET-APPARATE, OF EISENACH, THURINGIA, GERMANY.

INTERNAL-COMBUSTION LOCOMOTIVE. i

Application led January 13, 1925, Serial No. 2,202, and in Germany September 22, 1923.

Our invention relates to improvements in gearing for locomotives driven by internal-combustion engines, and more particularly by Diesel motors, or by turbines as well as for similar technical uses where it is a question of coupling an engine that doesnot start readily under load or an engine the angular velocity or direction of rotation of which is invariable or can only be varied with difficulty. with a shaft theL angular velocity or direction of rotation of which has to be varied within wide limits. For the sake of simplicity the invention will be discussed hereunder mainly in its application to the actuation of locomotives with Diesel-motor drive without any limitation of the invention to this province being thereby implied.

The driving of the main-line locomotives b v means of Diesel motors or turbines proves a particularly hard problem, apart from the difliculties, which have already been indicated above. on account of the magnitude of the inertia forces to be overcome in starting and in changing speed, and also in reversing. In the overcoming of these difficulties the construction and arrangement of the gearing transmitting the driving power from the motor to the axles of the locomotive plays a decisive part. Our invention starts from a spur gearing which substantially embraces two shafts the primary shaft communicating with the motor and the secondary shaft connected with the locomotive parts to be driven, upon which shafts the interengaging gear wheels are arranged, partly loose and partly fast the loose wheels being adapted to be coupled to their shafts at will. This coupling, as well as the coupyling of one gear shaft or the other to the motor shaft or to the axles of the locomotive as the case may be is effected b electrically operated means, a member o't an \lectro magnetic clutch f. i. mounted loose on the corresponding shaft being associated to each of the lose gear wheels, and this member, by exciting the correspondingmagnet winding, being brought into frictional engagement with the other member of the clutch, which is mounted fast upon its shafts. The coupling of the toothed Wheels, rotating in the opposite direction of a reversing gear ot' substantially the usual type is also effected with the aid of electrically operated coupling means.

Our invention relates more particularly to the special arrangement of the gear wheels with their electrically operated clutchesv in relation to the gear casing, to the distribution of the fast and loose gear wheels and the coupling of them to one gear shaft or the other, and to the arrangement and supporting of additional gear shafts.

Further objects of our invention will more clearly appear from the following specification. f,

In the accompanying Vdrawings our invention is illustrated by way of example in several constructional forms` wherein,

Figure 1 shows a locomotive constructed according to our invention, on the lett in side elevation and on the right in longitudinal sectional elevation through the gearing. Figure 2 shows on a larger scale y'therear part of the gearing in horizontal section on the line II-II in Figure 1.

Figure 3 illustrates, also in horizontal section through thev gearing and on a larger scale, another constructional form` with gear shafts arranged transversely to the motor shaft.

Figure 4 shows on a still larger scale a longitudinal sectional elevation through a third constructional form of the gearing connecting the motor of the locomotive with the rotating axles.

In the constructional form according to Figure 1 the driving motor resting on the frame of the locomotive is denoted by A, and in the present case is shown as a Diesel engine. The motor shaft 23 carries a clutch 20, which is electromagnetically operated. The detailed construction of this clutch is hereinunder described more fully in connection with Figure 4. The clutch 20 enables the motor shaft 23 to be coupled to the primary shaft 2 of the change speed gear, which is enclosed on all sides by a casing 1. Below the shaft 2 in the casing 1 1s supported the secondary gear shaft 11. On the shaft 2 are mounted three toothed wheels 3, 4 and 5 of different diameters, which are at all times in gear with 'three toothed wheels 1.2, 13 and 14, respectively, mounted on the secondary shaft l1. The toothed wheels 4 and 5 are keyed fast to the shaft 2, while the toothed wheel 3 is rotatably mounted on the shaft 2. Similarly the co-acting toothed wheels 13 and 14 are loose on the shaft 11. while the toothed wheel 12 gearing with the wheel 3 is mount ed fast on the secondary shaft. The toothed wheels 3, 13 and 14 mounted loose on their shafts are rigidly connected with the electromagnet clutch members 7, 8 and 9 respectively, which are likewise rotatably mountedion the shafts in question, while the co-acting bodies of these clutches are rigidly connected with the said shafts` So that when the magnet winding of each individual clutch is excited, the Clutch member connected with the associated toothed wheel is brought into frictional contact with the clutch member which is mounted fast on the shaft, and is thereby coupled to the associated shaft.

Underneath the second gear shaft 11l is supported a third gear shaft 43, to which is rigidly secured a toothed wheel 44 which is constantly in mesh with the wheel 12. The shaft 43 carries on its rearwardly directed end a bevel wheel 45, which is constantly in mesh with two bevel wheels 46, 47 (Figure 2). The wheels 46 and 47 are mounted loose on a shaft 48 running transversely to the rest of the gear shafts, and are rigidly connected with the rotatable members 51 of two electro-magnetic clutches 50a and 50h, likewise arranged on the shaft 48, by sleeves surrounding the intervening parts of the shaft 48. The magnet bodies 52 of these clutches are mounted fast on the shaft 48. Vhen the magnet winding of one of the individual clutches is excited the associated armature disc 53, which is axially displaceable but not rotatable relatively to the movable clutch member 51, is attracted and brought into frictional engagement with the fast clutch member 52. In this manner is effected the coupling of the bevel wheel with the clutch member 51 in question. According as the clutch 50a or the clutch 50b is actuated the bevel wheel 47 and 46 is connected to the shaft 48, thus causing this shaft to rotate in one direction or the other. The gear casing 1, as indicated in Figure 2, preferably encloses only the gear wheels 45, 46 and 47, but leaves the clutches 50a and 50b outside.

Thetransverse shaft 48 is preferably arranged in a common horizontal plane with the axles 55 of the locomotive (compare Figure 1). The power-transmission is effected, in the case of the constructional form illustrated, in the usual way, b means of a connecting rod drive, upon w ich act two cranks 49 mounted on the'ends of the transverse shaft 48.l

The individual clutches 7, 8 and 9 belong ing to the loose gear wheels 3, 13 and 14 are constructed, in a manner known in itself, as so-called laminated or multiple-disc clutches, as shown in the illustration of the clutch 7 in the constructional form according to Figure 4, while the main clutch 20, as is also evident from Fi ure 4, as Well as the clutches 50a and 50h (Tcompare Figure 2) belonging to the reversing gear 45, 46, 47 are constructed as ordinary two-surface clutches. The construction as laminated clutches permits of a very compact construction with comparatively high capacity, which is very important for the application of the invention to locomotive-driving, on account of the limited space available. For the main clutch 20 arranged outside the gear casing, on the other hand, the deciding factor is good adjustability, in conjunction with the power to resist excessive stress and wear arising from the slipping of the members that are in frictional contact with one another.

In order to keep the individual clutches 7, 8 and 9 as small as possible it is advisable to locate them on the primary gear shaft, as this normally has the greatest angular velocity, and on this account the torques to be transmitted by the individual clutches have the smallest value. In the case of the constructional form according to Figure 1 this principle is only carried out with regard to clutch 7. ln the construction according to Figure 4, however, all the individual clutches 7, 8, 9 and 10 are located on the primary shaft 2. It is important that in any case the electra-magnetie clutches for the higher ratios, that is to say, those that transmit the greatest number of revolutions per minute to the axles of the locomotive, should be mounted on the primary gear shaft, while the clutches for the other ratios may be applied in part to the secondary gear shaft. This idea is embodied in Figure 1, where the gear wheel 3 belonging to the clutch 7 deals with the highest ratio. In this way the result may be attained that in no case, when the various speeds are thrown into operation, do any members, and particularly the sensitive electro-magnetic clutches, assume excessively hi h angular velocities, as the clutches on tie primary gear shaft rotate at all times with the same angular velocity as the driving motor, for which the clutches are constructionally suitable. The clutches on the secondary gear shaft rotate when one of them is thrown into engagei'nent, at` a lower an ular velocity, while if one of the clutches ealing with the higher ratios is thrown into engagement, the clutches mounted on the secondary shaft also rotate only with the same angular ve.- locity as the primary gear shaft, or at any rate only quite a little slower or faster, so that in particular the sensitive exciting windings of the clutches are never excessively stressed. In the case of a gear equipped with three speeds according to Figure 1, preferably only the clutch for the highest ratio is locate on the primary shaft, while the clutches for the lower ratios are arranged on the secondary shaft. The highest ratio, which in the case illustrated is dealt with by the clutch 7, is preferably made about 1:1.

The arrangement of the third gear shaft according to Figure 1 offers in the first place the advantage that from this shaft auxiliary machines, such as the generator serving for the production of the exciting current for the electro-magnetic clutches, a lighting dynamo, a compressor for the air brakes or the like, can be driven in a simple manner; furthermore it makes it possible to pass on the main driving power in a favorable manner, as the position of the third shaft ca n very easily be suitably selected from this point of view. In particular the third gear shaft admits of being located quite low down between the axles of the locomotive in which case for normal working, which corresponds in the construction according to Figure 1 to the engagement of the clutch 7 the transmission of power can be effected as directly as possible and with the best useful effect in one plane formed by the gear wheels 3, 12 and 44, which is of great importance for the working of powerful main-line locomotives.

The individual clutches 7, 8 and 9 and so forth, which have to be actuated at each change of speed are thereby very heavily stressed; furthermore on account of their construction as laminated clutches, they are particularly sensitive to overloads. It is therefore advisable to arrange these clutches as far as possible outside the gear casing, where they can be conveniently watched over, and where also the cooling is more easily effected. In Figure 3 is illustrated a constructional form of the drive wherein this idea is carried out for the individual clutches belonging to the change-speed gear wheels, in the manner already described in the explanation of Figure 2. In this construction the gear shafts 2, 11 and 43 are supported in the gear casing transversely to the motor shaft 23. The main clutch 20 is inserted between the motor shaft 23 and an intermediate shaft 23 projecting into the gear casing, this intermediate shaft being at' all times in connection through a bevel gear 60 with the primary gear shaft2. On the shaft 2 is mounted fast a toothed wheel 3", which is always in mesh with a toothed wheel 12 mounted loose on the secondary shaft 11. The toothed wheel 12 is connected with the member of an electro-niagnetic clutch 7F mounted loose on the shaft 11, the other member of which is mounted fast on the shaft 11. Further there is mounted fast to this shaft a toothed wheel 12b, which is permanently in mesh with a toothed wheel 44a, which is arranged fast on the shaft 43. This shaft again carries on its two ends cranks 49, which are connected by means of coupling rods with the cranks of the axles of the locomotive.

Moreover the primary shaft 2 carries loose two toothed wheels 4aand 5, which mesh with toothed wheels 13 and 14a respectively mounted fast on the secondary shaft 11. The wheels 4*l and 5a are connected by means of sleeves 62, led out of gear casing 1 through the bearing 61, with the movable members of the electro-magnetic clutches 8a and 9aL respectively, mounted outside the casing ori the ends of the shaft 2, in a manner similar to that described above in explaining the construction of the reversing gear according to Figure 2.

If the main clutch 2O is engaged, the primary shaft 2 rotates continuously in consequence of the connection through the bevel gear 60. Also the toothed wheel 12at of the secondary gear shaft continuously rotates, with the movable member of the clutch 7 connected therewith. If the locomotive is to be set in motion, first the clutch 9a is engaged, whereby the toothed wheel 5a is connected fast to the primary shaft. On account of the constant engagement between the wheels 5a and 14, and also 12b and 44, the shaft 43 is set in rotation with the latter, and rotates at the lowest speed, corresponding to the transmission ratio between. the wheels 5 and 14, After the locomotive has been started in this manner the next speed is thrown into gear. To this end the excita tion of the clutch 9a is interrupted and the clutch 8a switched on. By this means the secondary shaft 11 is coupled to the primary shaft 2, and the shaft 43 is driven at au increased speed corresponding to the greater ratio between the wheels 4a and 13a. Finally` after switching of the clutch 8, the clutch 7a is engaged, whereby the greatest ratio between the wheels 3a and 12*l comes into operation. The locomotive then runs at its highest speed, which is the normal speed. The clutch 7a, which transmits the normal drive, is only rarely put into operation, so that here a slipping of the clutch members in frictional engagement with one another only occurs exceptionally. This clutch can therefore without hesitation be arranged within the gear casing, in contrast with the clutches 8a and 9, which are actuated comparatively often and are therefore severely stressed. By locating these clutches outside the casing such severe stressing ceases to be hazardous, as the clutches are firstly easier to cool, and furthermore are also conveniently accessible, and finally they can also be more liberally diinensioned than if they were lodged within the narrow gear casing.

A further possibility of protecting the individual clutches against excessive stresses is embodied in the constructional form illustrated in Figure 4. Here again all the individual clutches 7, 8, 9 and 10, with the pairs of gear wheels 3 and 12, 4 and 13, 5 and l-L and 6 and 15 respectively belonging thereto, are fitted into the gear casing. The primary shaft 2 is again connected with the shaft coming from the motor through a main clutch 20. This clutch consists essentially of the disc body mounted fast on the shaft 2 and of the co-acting body 24, which is mounted fast on the shaft 23 and which contains the exciting winding this co-acting body, together with the armature disc 19, forming the magnetic system. The armature disc 19 is movably guided in an axial direction by means of a slide ring 21 upon a hub-like projection of the member 17. The twisting of the armature disc 19 relatively to the part 17 is prevented by bolts screwed into the disc 19, which are loosely guided by corresponding holes bored in the part 17. By springs 22 distributed over the periphery of the body 17 the armature disc 19 is normally drawn away from the magnet body 24. By 28 is denoted a friction ring connected with the magnet body 24e, which friction ring, when the clutch is actuated. deals with the frictional engagement with the armature disc 19. The exciting current is supplied to the clutch through the medium of slip rings 26.

The individual clutches 7, 8, 9 and 10 are again constructed as multiple-disc clutches. The part 17a, which, together with the associated toothed wheel, is mounted loose on the shaft 2 and encloses the system of laminated multiple discs in a bell-like manner, is connected through the medium of an armature disc 19, when the Winding is excited. which the co-acting body containing the exciting winding and mounted fast on the shaft 2, whereby the coupling of the toothed wheel in question to the primary shaft 2. is effected and consequently also the 'connecting of the secondary shaft 11. The supplying of the exciting current to the individual clutches is effected through the medium of slip rings 16.

In the left-hand lower'corner of Figure 4 is illustrated diagrammatically a device 29 with the aid of. which the putting-in of the various speeds is preferably effected. By 30 is indicated a disc rotatable about a pivot 31, this disc carrying a series resistance 32, subdivided into separate stages. Over the contacts of this resistance can be moved a switch lever 33, which is also rotatableabout the pivot 31, and which is electrically connected with one of the slip rings 26 of the main clutch 20 through a lead 34. The other slip ring is in direct connection with a source of current 27, while the other pole is connected through a lead 35 to one end of the series resistance 32. The switch lever 33 can engage by means of a further Contact piece 36 with a series of contacts 37 each of which is in connection, through the medium of the slip rings 16, with one end of one of the exciting windings of one of the individual clutches 7, 8, 9 or 10. The other ends of these windings are connected through the lead 3S with one pole of a second source of current 39, the other pole of which is connected to the lead 34 and is thereby put into communication with the switch lever` The switch lever 33 is rotatable independently of the disc 30, but it is connected therewith by a spring 40 in such a way that When the lever 33 is rotated in the direction of the arrow the disc 30 is caried along by it, the spring 40 being stressed. This carryingalong is however retarded by a liquid brake 41. The piston rod of this li uid brake is provided with a rack, whic meshes a toothed wheel 42 connected fast' to the disc 30.

The method of working of the device hereinbefore described is as follows: After the motor of the locomotive has first been started running light, the main clutch 20, next sets the primary shaft in motion, by switching the exciting current, which is preferably done gradually by cutting out a series resistance. the toothed wheels 3, 4, 5 and 6 mounted loose on this shaft, which mesh with their toothed wheels 12, 13, 14 and 15 mounted fast on vthe shaft 11, remaining at rest. The position of the switch lever 33 corresponding to this state of affairs is shown in Figure 4. If the locomotive is now to be started on its journey the switch lever 33 is shifted on to the first contact of the series 37, belonging to the clutch 10. The disc 33 with the series resistance 32 cannot immediately follow this movement on account of the restraint by the brake 41. A relative displacement therefore occurs between the disc 30 and the lever 33, which is simultaneous with the interposition of the resistance 32 in the exciting-current circuit of the main clutch 22. Thus as soon as the contact 36 of the lever 33 has reached the first of the contacts 37, whereby the individual clutch 10 is engaged, the attracting force of the main clutch is weakened correspondingly to the resistance connected in series therewith, so that when the shock occurs upon the attraction of the clutch l0. it is not the latter but the main clutch 20 that slips. in which case the speed of thc loco motive, and with it the angular velocity of the gear shafts` isgradually raised. Meanwhile the disc 30, with the series resistance 32, hastens to overtake the switch lever 33, so that after a certain time the first stud of the resistance 32 again comes into contact with the switch arm 33, whereby the resistance is switched out of the excitingcrrrent circuit of the main clutch again, so that the attractive force of the main clutch, and with it the maximum torque transmissible thereby, again assumes its normal value. In a corresponding manner the engaging of the further speeds of the gea-r is completed Each time during the engaging of the clutch in question the attracting force of the main clutch is weakened, so that the shocks are always taken up by the main clutch. As the main clutch arranged outside the gear casing can easily be constructed of comparatively large dimensions, and as the cooling is also easy to carry out, the repeated and rapidly successive stressing of the main clutch occuring in the traction does not lead to any sort of disturbances. The individual clutches in the case of this method of working are, as good as if not stressed at all by friction, so that firstly they can be very compactly built by constructing them as clutches` with multiple laminated discs, and on this account they can be lodged without difficulty together with the gear wheels, in a common casing.

We claim:

1. In a locomotive, a motor, a driving axle, a change-speed gear interposed between said motor and said driving axle, said gear comprising a primary shaft and a secondary shaft and gear wheels meshing with one another in pairs, and mounted in part fast and in part loose on said shafts. electrically actuated coupling means adapted to rigidly secure each of said loosely mounted gear wheels to its shaft, more than one of said gear wheels being mounted on the secondary shaft, at least one of the gear wheels mounted on the secondary shaft being rigidly secured to and meshing with one of said loosely mounted gear wheels.

2. In a locomotive, a motor, a driving axle, a change-speed gear interposed between said motor and said driving axle, said gear comprising a primary shaft and a secondary shaft and gear wheels meshing with one another in pairs, and mounted in part fast and in part loose on said shafts, electrically actuated coupling means adapted to rigidly secure each of said loosely mounted gear wheels to its shaft, more than one of said gear wheels being mounted on the secondary shaft. at least one of the gear wheels mounted on the secondary shaft being rigidly secured to this shaft, a third shaft adapted to transmit the power from said secondary shaft to said driving axle, a further gear mountedon said third shaft and meshing with one of gear Wheels rigidly secured to the secondary shaft.

3. In a locomotive, a vmotor, a driving axle, a change-speed gear interposed between said motor and said driving axle, said ear comprising a primary shaft and a secon ary shaft andgear Wheels meshing with one another in pairs, and mounted in part fast and in part loose on said shafts, electrically actuated coupling means adapted to rigidly secure each of said loosely mounted gear wheels to its shaft, more than one of said gear wheels being mounted mi the secondary shaft, at least-` one of the gear wheels mounted on the secondary shaft being rigidly secured to this shaft, a third shaft adapted to transmit the power from said secondary sha-ft to said driving axle, a further gear mounted on said third shaft and connected by means of one of the gear Wheels rigidly secured to the secondary shaft, to one of the gear wheels arranged loose on the primary shaft. v.

4. In a locomotive a motor, a driving axle, a change-speed gear interposed between said motor and saidI driving axle, said gear comrising a primary shaft, asecondary shaft eneath the primary shaft and gear Wheels meshing with one another in pairs, and

mounted in part. fast and in part loose onsaid shafts, electricall actuated coupling means adapted to rigid y secure each of said loosely mounted gear wheels to its shaft, more than one of said gear Wheels and at least one of said coupling means being arranged on said primary shaft, more than one of said gear wheels being mounted on the secondary shaft, at least one of the gear wheels mounted on the secondary shaft being rigidly secured to this shaft, a third shaft beneath said secondary shaft, and adapted to transmit the power from said secondary shaft to said driving axle, a further gear mounted on-said third shaft and meshing with one of the gear wheels rigidly secured to the secondary shaft.

5. In a locomotive having a plurality of axles, a motor, a change-speed gear operatively interposed between said motor and said axles, said gear comprising a primary shaft, a secondary shaft beneath the primary shaft and gear wheels meshing with one another in pairs, and mounted in part fast and in part loose on said shafts, eleotrically actuated coupling means adapted to rigidly secure each of said loosely mounted gear Wheels to its shaft, more than one of said gear wheels and Iat least one of said coupling means bein arranged on said primary shaft, more tian one of said gear wheels mounted on the secondary shaft, at least one of the gear wheels mounted on the secondary shaft being rigidly secured to this shaft, a third shaft beneath said secondary shaft and disposed between two of said axles, said 'third shaft being adapted to transmit the power from said Secondary shaft to one of said axles, a further gear mounted on said third shaft and meshing with one of the gear wheels rigidly secured to the secondary shaft.

6. In a locomotive having a plurality of axles lying substantially in a common horizontal plane, a motor, a changesp eed gear operatively interposed between said motor and one of said axles, said gear com rising a primary shaft and a secon ary sha t, gear wheels meshing in pairs with one another and mounted in part fast and in (part loose on said shafts, electrically actuate couplin means mounted on said shafts and adapte to rigidly secure each of said loosely mounted gear wheels to its shaft, a third shaft beneath said secondary shaft and adapted to transmit the power from said secondary shaft to one of said exles, a further gear mounted on said third shaft and meshing with one of the gear wheels rigidly secured to the secondary shaft.

7. In a locomotive having a plurality of axles disposed substantially in a common horizontal plane, a motor, a change-speed gear operatively interposed between said motor and one of said axles, said gear comprising a primary shaft and a secondary shaft, gear wheels meshing in pairs with one another and mounted in part fast and in part loose on said shafts, electrically actuated coupling means mounted on said shafts and adapted to rigidly secure each of said loosely mounted gear wheels to its shaft, a third shaft beneath said seconda-ry shaft and disposed between two of said axles, said third shaft being adapted to transmit the power from said secondary shaft to one of said axles, a further gear mounted on said third shaft and meshing with one of the ga; wheels rigidly secured to the secondary s a t.

8. In a locomotive, having a motor, a motor shaft, a driving axle, a change-speed gear operatively interposed between said motor and said drivin axle, said gear comprising a primary shaft journaled with said motor shaft, a secondary shaft, pairs of gear wheels meshing with one another and mounted in part fast and in part loosely on said gear shafts, said pairs having different speed transmitting ratios, electrically actuated coupling means associated to each of said pairs, those of said coupling means associated to the gear wheel pairs of higher ratio beiitg mounted on said primary shaft,

the coupling means associated to other gear wheel pairs being mounted on the secondary gear s aft.

9. In a locomotive, having a motor, a motor shaft, a driving axle, a change-speed gear operatively interposed between said motor and said axle, said gear comprising a primary shaft operatively connected to said motor shaft and a secondary shaft, three pairs of gear wheels of different speed transmitting ratios, each air comprising a fast and a loose gear wheel), electro-magnetic clutches associated to each of said pairs and adapted to rigidly couple said loose. wheels to their respective shafts, that of said clutches associated to the pair of the high est speed transmitting ratio being mounted on said primary shaft, the two other clutches being mounted on the secondary shaft.

10. In a locomotive, having a motor, a motor shaft, a driving axle, a change-speed gear operatively interposed between said motor and said axle, said gear comprising a primary shaft operatively connected to i said motor shaft and a secondary shaft, three pairs of gear wheels of different speed transmitting ratios, each pair comprising a fast and a loose gear wheel, electro-magnetic clutches associated to each of said pairs and adapted to rigidly couple said loose wheels to their respective shafts. that of said clutches associated to the pair of the highest speed transmitting ratio being mounted on said primary shaft, the two other clutches being mounted on the secondary shaft, a third sha-ft beneath said secondary shaft and adapted to transmit the power from said secondary shaft to said driving axle, a further gear mounted on said third shaft and meshing with one of said fast gear wheels.

l1. In a locomotive, having a motor, a motor shaft, a driving axle, a change-speed gear operatively interposed between said motor and .said axle, said gear comprising a primary shaft operatively connected to said motor shaft and a secondary shaft, three pairs of gear wheels of different speed transmitting ratios, each pair comprising a fast and a loose gear wheel, electro-magnetic clutches associated to each of said pairs and adapted to rigidly couple said loose wheels to their respective shafts, that of said clutches associated to the pair of the highest speed transmitting ratio being mounted on said primary shaft, the two other clutches being mounted on the secondary shaft, a third shaft adapted to transmit the power from said secondary shaft to said driving axle, a further gear mounted on said third shaft and meshing with one of said fast gear wheels. Y

12. In a locomotive, having a motor, a motor shaft, a driving axle, a change-speed and reversing gearoperatively interposed between said motor and said axle, said gear comprising a plurality of gear shafts, pairs of gear Wheels meshing with one another and mounted in part fast and in part loosely on said gear shafts, two reversing` gem' wheels loosely mounted on one of said gear shafts and meshing permanently with one of said fast mounted gear wheels, electro-magnetic clutches adapted to rigidly couple the one or the other of said reversing gear 10 wheels to their shaft.

In testimony whereof we have signed our names to this specification.

ERICH MRONGOVIUS. ERICH SCHVETER. 

